1. Technical Field
The present invention relates to a piezoelectric element, a liquid ejecting head, and a liquid ejecting apparatus.
2. Related Art
A piezoelectric element used for a liquid ejecting head or the like is an element in which a piezoelectric film made of piezoelectric materials having an electromechanical transduction function is interposed between two electrodes. The piezoelectric film is made of crystallized piezoelectric ceramics, for example.
An example of a liquid ejecting head using such a piezoelectric element is, for example, an ink jet recording head in which a part of a pressure chamber which communicates with a nozzle opening discharging ink droplets is configured by a vibrating plate, the vibrating plate is deformed by the piezoelectric element to apply pressure to ink of the pressure chamber, and the ink droplets are discharged through the nozzle opening. Two types of ink jet recording head are in practice: One using a piezoelectric actuator in a longitudinal vibration mode which expands and contracts in the axial direction of the piezoelectric element, and one using a piezoelectric actuator in a flexural vibration mode. For such actuators, a piezoelectric element capable of obtaining a large strain with a low drive voltage, that is, a piezoelectric element with a large displacement is in demand for high density arrangement.
Here, in order to increase piezoelectric constant and remove variation, a piezoelectric element which includes a PZT and an electrode is known: in the PZT, Zr and Ti has a composition ratio so as to form a perovskite structure with rhombohedral crystals at room temperature and the crystals are oriented in a (100) direction (JP-A-11-233844).
However, such a piezoelectric element cannot have a sufficient displacement. In addition, such a problem is not limited to a liquid ejecting head represented by an ink jet recording head, and also arises in other piezoelectric elements.